It's a Windows Media Center plug-in that's simplicity itself to use. Just click on the Boxee option in the WMC main menu to close WMC and open Boxee, and when you're done watching your content just close out to automatically bring up WMC again. Even better: the switch can be made with your remote, so you never have to leave your La-Z-Boy.

You can get it as a free download now from here, but know that it's only compatible with Windows 7 and, sadness, won't work on your Xbox. [Boxee Integration App via Lifehacker]